BILLY Joel should have tried to “Get It Right the First Time” with soon-to-be ex-wife Katie Lee Joel. Sources say the aging pop star, who is legally separated from Katie Lee, is completely distraught over the June breakup and wants to get his woman back.

According to friends of the couple, “Billy is obsessed with her” and is trying to rekindle the relationship. The two split because Katie Lee — a TV food critic and chef — wanted to have kids and a family, and Joel did not. Adding to the tension were Katie Lee’s many nights out with designer Yigal Azrouel.

“Billy never wanted to go out with her. She wanted to have fun and promote herself, so she started hanging out with Yigal,” a source told us. Insiders say that Joel now believes Azrouel and Katie Lee were never more than friends and he’s doing everything he can to win her back. But a friend of Katie Lee told us, “They’re not getting back together. She is trying to move on.”

And it looks like she’s doing just that. A spy who saw Katie Lee at the Metropolitan Club Thursday night during the Moet party for Meryl Streep‘s new movie, “Julie & Julia,” said she was “talking about visiting Paris, and mentioned going there on her own to study cooking.”

The following morning, Katie Lee was spotted at Norma’s in the Parker-Meridien hotel “chatting up and flirting with [E! correspondent] Ben Lyons.”

Joel, however, is not enjoying the same carefree life. He recently postponed two concerts with Elton John upstate because of “flu-like symptoms.”

Last month, Page Six reported that Joel was dating former soap star Alex Donnelley, but it seems that romance has fizzled.

A rep for Katie Lee had no comment. Joel’s spokeswoman told us, “The split between them is amicable. They remain friendly, and they do communicate.”